Phoenix Content Negotiation

gistfile1.ex

# Controller option 1, implicit render selected based on format
defmodule MyApp.UserController do
  use Phoenix.Controller
  
  def show(conn, %{"id" => id}) do
    render conn, :show, user: Repo.get(User, id)
  end
end

# Controller option 2, explicit render with format pattern match
defmodule MyApp.UserController do
  use Phoenix.Controller
  
  def show(conn, %{"id" => id, "format" => "html"}) do
    render conn, "show.html", user: Repo.get(User, id)
  end
  def show(conn, %{"id" => id, "format" => "json"}) do
    render conn, "show.json", user: Repo.get(User, id)
  end
  def show(conn, %{"id" => id, "format" => "xml"}) do
    render conn, "show.xml", user: Repo.get(User, id)
  end
end

# View
defmodule MyApp.UserView do
  use MyApp.View
  
  def render("show.json", %{user: user}) do
    %{
      name: user.name,
      email: user.email
    }
  end
  
  def render("show.xml", %{user, :user} do
    XMLBuilder.build(user)
  end
  
  # render("show.html", ...) defined by show.html.eex template automatically
end